Preparation and in vitro characterization of remdesivir-loaded liposomes for inhalation / 中国药科大学学报

@#Remdesivir-loaded liposomes for inhalation were prepared and the in vitro properties were evaluated. Firstly, preparation methods of remdesivir-loaded liposomes were screened, and single-factor experiments were conducted to optimize the prescription and preparation process. Then the physical property, deposition ratio and aerodynamic particle size distribution of remdesivir-loaded liposomes suspension for inhalation were comprehensively evaluated. As a result, the optimal liposomes were prepared by the thin-film dispersion method with pH 6.5 phosphate-buffered saline as the hydration medium. In the prescription, the ratio of drug to DPPC was 1∶20; the cholesterol accounted for 10% of total lipids; and 20% DSPE-mPEG 2000 was added as stabilizer.4% trehalose was added as lyoprotectant when lyophilizing to obtain ideal appearance, good stability and a small particle size change after reconstitution. Remdesivir-loaded liposomes were spherical with smooth surface and uniform particle size distribution under transmission electron microscope. In vitro release tests showed no significant change for release curves of remdesivir-loaded liposomes suspension before and after nebulization. Deposition experiments indicated that the fine particles fraction of liposomes was 51.4%, and the mass median aerodynamic diameter was less than 5 μm measured by next generation impactor. To sum up, remdesivir-loaded liposomes for inhalation with high encapsulation efficiency and stability can achieve a suitable particle size distribution to effectively deposit in the lung after nebulization, which provides a new approach for the treatment of COVID-19.

Revisión de los perfiles aerodinámicos apropiados para turbinas eólicas de eje horizontal y de pequeña escala en zonas boscosas / A review of horizontal axis small wind turbine blades suitable for wooded areas / Revisão dos perfis aerodinâmicos apropriados para turbinas eólicas de eixo horizontal e pequena escala nas zonas arborizadas

Resumen Introducción: la energía eólica ha crecido de forma acelerada en los últimos 20 años y los sitios para instalar parques eólicos se empiezan a agotar. Las turbinas eólicas de pequeña escala representan una alternativa viable, en particular en zonas boscosas: de bajo potencial eólico y alta turbulencia. Objetivo: presentar una revisión de los perfiles aerodinámicos para aerogeneradores de pequeña escala, para determinar su posible aplicación en zonas boscosas. Materiales y métodos: se efectúa una revisión literaria en las bases de datos Web of Science y Scopus, sobre turbinas eólicas de pequeña escala de eje horizontal, en las revistas Energy, Journal of Wind Engineering and Industrial Aerodynamics, Renewable and Sustainable Energy Reviews y Renewable Energy, entre otras. Se define una clasificación de tres grandes grupos para los perfiles aerodinámicos: de uso muy frecuente, de uso con frecuencia media y de uso con baja frecuencia. Resultados: los perfiles de uso muy frecuente son el SG6043, S809 y NACA0012, siendo el primero de ellos el que presenta mejor desempeño aerodinámico. A pesar de esto, otros perfiles como el SH3055 son ampliamente usados en turbinas eólicas de pequeña escala. Conclusiones: un perfil adecuado para una turbina eólica de pequeña escala para zonas boscosas debe ser diseñado para regulación por pérdida (stall) y poseer una alta robustez ante cambios de rugosidad superficial. El perfil con mayor potencial, según la literatura para esta aplicación, es el SG6043, siendo 110 % y 85 % más eficiente que NACA0012 y S809, respectivamente, para un Re de 2 x 105; empero, se requiere más investigación en temas como desempeño aerodinámico de los perfiles ante altos niveles de turbulencia.

Abstract Introduction: Wind energy has grown rapidly in the last 20 years and sites to install full-scale wind farms are starting to run out. Small-scale wind turbines represent a feasible alternative, particularly in forested areas of low wind potential and high turbulence. Objective: to present a review of the aerodynamic profiles for small-scale wind turbines, to determine their possible application in wooded areas. Materials and methods: a review of small-scale horizontal axis wind turbines is carried out using the Web of Science and Scopus databases mainly on the journals: Energy, Wind Engineering and Industrial Aerodynamics, Renewable and Sustainable Energy Reviews, and Renewable Energy. A classification of three large groups is defined for the aerodynamic profiles: very frequent use, medium frequency use and low frequency use. Results: the profiles of very frequent use are the SG6043, S809 and NACA0012, the first of them is the one having the best aerodynamic performance. Despite this, other profiles such as the SH3055 are widely used in the small-scale wind turbine field. Conclusions: a suitable profile for a small-scale wind turbine for forested areas should be designed for stall regulation and have low sensitivity against changes in surface roughness. The profile with the greatest potential, according to the literature for this application, is the SG6043, being 110 % y 85 % more efficient than NACA0012 and S809, respectively, for a Re of 2 x 105; however, more research is required on issues such as aerodynamic performance of the profiles at high levels of turbulence.

Resumo Introdução: a energia eólica há crescido de forma acelerada nos últimos 20 anos e os sítios para instalar parques eólicos empeçam a diminuir. As turbinas eólicas de pequena escala representam uma alternativa viável, em particular nas zonas arborizadas: de baixo potencial eólico e alta turbulência. Objetivo: apresentar uma revisão dos perfis aerodinâmicos para aerogeradores de pequena escala, para determinar uma possível aplicação nas zonas arborizadas. Materiais e métodos: efetuou-se uma revisão literária nas bases de dados Web of Science e Scopus, sobre turbinas eólicas de pequena escala de eixo horizontal, nos jornais Energy, Journal of Wind Engineering and Industrial Aerodynamics, Renewable and Sustainable Energy Reviews e Renewable Energy, entre outras. Define-se uma classificação dos três grandes grupos para os perfis aerodinâmicos: de uso muito frequente, de uso com frequência meia e de uso com baixa frequência. Resultados: os perfis de uso muito frequente são o SG6043, S809 y NACA0012, sendo o primeiro deles o que apresenta melhor desempenho aerodinâmico. Apesar disso, os perfis como o SH3055 são amplamente usados nos negócios das turbinas eólicas. Conclusões: um perfil adequado para uma turbina eólica de pequena escala para zonas arborizadas deve ser projetado para regulação por stall e possuir uma alta robustez ante mudanças na rugosidade superficial. O perfil com maior potencial, segundo a literatura e para essa aplicação é o SG6043, sendo 110 % e 85 % mais eficiente que NACA0012 e S809, respectivamente, para um Re de 2x 105, no entanto, requere mais investigação em temas como o desempenho aerodinâmico dos perfis

Research Progress of Bobsleigh Aerodynamics / 医用生物力学

The aerodynamic characteristics of bobsleigh play a very important role in the result of the race. In order to improve the performance, it is necessary to optimize the bobsleigh aerodynamics and reduce its aerodynamic drag as much as possible. Foreign scholars has mainly used computational fluid dynamics (CFD) numerical simulation, wind tunnel experiments and other methods to study the aerodynamic characteristics and optimize drag reduction method, but the relevant research has not yet been carried out in China. In order to have a clear understanding of the technical requirements of bobsleigh aerodynamic optimization and drag reduction, the research result of bobsleigh aerodynamics in recent 20 years have been systematically combed, mainly including numerical simulations and wind tunnel experiments of aerodynamic optimization of bobsleigh body shape and athletes’ positions and attitudes in the bobsleigh, and the possible future development direction of bobsleigh aerodynamics research has been put forward: the systematic study of bobsleigh aerodynamics optimization and comprehensive assessment of bobsleigh aerodynamic drag reduction effects; the study on the interaction between athlete glide control and bobsleigh aerodynamics. These studies will provide an important scientific guidance for the optimization and improvement of bobsleigh sports equipment and the daily training of athletes.

The changes of aerodynamic parameters in the tracheal stenosis before and after stent implantation and their clinical significance / 介入放射学杂志

Objective To explore the changes of the aerodynamic parameters in tracheal stenosis before and after stent implantation,and to discuss the significance of these changes.Methods The clinical data of 20 patients with tracheal stenosis,who were treated with stent implantation,were collected,and the clinical features as well as imaging findings were summarized.Using the computer fluid dynamics analysis software,the airflow dynamics simulation study on tracheal stenosis before and after stent implantation was conducted.The aerodynamic parameters of the region of interest were recorded and statistically analyzed.The mean values of quantitative data were compared by using t-test,and P＜0.05 was considered to be statistically significant.Results The nature of tracheal stenosis was malignant in all 20 patients,which was caused by tumor compression and invasion.Stenosis degree ＞50％ was seen in 18 patients,the stenosis was located in the middle of trachea in 10 patients,segmental stenosis was observed in 15 patients,and eccentric stenosis was found in 17 patients.After stent implantation,the lumen area at previous tracheal stenosis site became (2.03±0.32) cm2,which was larger than (0.96±0.18) cm2 measured before stent implantation.The pre-stenting velocity at the stenotic site of trachea was (1764±1484) cm/s,which was higher than (688±434) cm/s of the post-stenting velocity.The pre-stenting velocity and volume flow measured at the left main bronchus entrance were (308±209) cm/s and (359±255) ml/s respectively,both of them were smaller than those measured at the right main bronchus entrance,which were (464±246) cm/s and (526±283) ml/s respectively,the differences were statistically significant (both P＜0.05).After tracheal stent implantation,the differences in the velocity and volume flow between the left main bronchus entrance and the right main bronchus entrance were not statistically significant.Conclusion The aerodynamic parameters in tracheal stenosis are characterized by the presence of a high velocity of air flow at the stenosis site,and the stenosis of trachea has an effect on the velocity and volume flow at both left and fight main bronchus entrances.Tracheal stenting can remarkably increase the lumen area at tracheal stenosis site,reduce the high velocity at the stenotic site and make the airflow smoother,and the bronchial airflow of the right and left side can be balanced.The airflow dynamics simulation of tracheal stenosis before and after stent implantation has a certain value for the pathophysiological study of tracheal stenosis and for the evaluation of therapeutic effect.

Numerical simulation of intranasal airlfow ifeld / 中国耳鼻咽喉头颈外科

[ABSTRACT]OBJECTIVETo explore the basic characters of the airflow-field in Chinese people's nasal cavity by computational fluid dynamics.METHODSThe three-dimensional, finite-element mesh were developed from Spiral CT imaging scans of nose of the 40 healthy Chinese people. Given the following spatial boundaries of the flow field: no-slip condition was imposed at the surface of the nasal airway walls; a standard atmosphere pressure condition was established at the inlet; a velocity vector was specified at the outlet (nasopharynx), which was obtained under the condition of aspiratory flow rate (12 L/min), the full Navier-Stokes and continuity equations were solved to obtain the airflow pattern.RESULTS1. The airflow passed mainly through left or right side of the nasal airway in the whole 40 cases (left 33, right 7),and the volume of air through the main-side is (320±28) ml while non-main-side (180±45) ml. 2. Airflow velocity: airflow of anterior nostrils, internal nostrils, the middle and inferior parts of the total meatus in the main-side were (5.01±2.12) m/s, (7.00±1.75) m/s, (5.08±1.55) m/s, (4.12±1.40) m/s respectively, and those in non-main-side were (2.01±0.94) m/s, (2.40±0.34) m/s, (1.99±1.0) m/s, (2.01±0.65) m/s respectively, which differences between the both sides were of statistical significance (allP0.05); 3. The airflow form appeared to be linear in the middle and inferior parts of the nasal cavity. 4. Velocity in maxillary sinus cavity was almost 0 m/s.CONCLUSIONThe airflow passes mainly through the middle and inferior parts of the meatus with higher velocity in laminar form and airflow of middle meatus, inferior meatus and olfactory cleft are low and the velocity were slow. Besides, airflow in maxillary sinus cavity diffuses free mainly.

Establishment and preliminary analysis of fluid dynamics model of the subjects with micrognathia / 实用口腔医学杂志

Objective:To establish a fluid dynamics model of upper airway before and after surgery and explore the changes of three-dimensional fluid dynamics in patients with micrognathia.Methods:A patient with micrognathia and severe obstructive sleep apnea-hypopnea syndrome(OSAHS)accepted CT scan before and six months after mandibular advancement operation.Computation-al fluid dynamics model was built on the base of CT scan by Mimics 1 0.01 and ANSYS ICEMCFD1 4.0.The internal flow of upper respiratory tract was simulated by ANSYS-FLUENT 1 4.0 and the results were analyzed by Tecplot.Results:Fluid dynamics model of upper airway was constructed before and after the surgery respectively.The volume of the upper airway of the patient increased from 37.284 cm3 to 44.498 cm3;the most narrow area of upper airway was located in the lower bound of pharyngopalatiae,and it was augmented from 1 .1 35 cm2 to 2.297 cm2;the minimum pressure was decreased from1 01 308 Pa to 1 01 272 Pa;the maximum air velocity increased from 3.476 m/s to 4.978 m/s.Conclusion:Mandibular advancement may correct the occlusal deformity,ex-panse the upper respiratory tract,decrease the negative pressure and maintain the patency of the airflow in the treatment of patients with micrognathia and OSAHS.

Influência da pedalada com os joelhos tangenciando o quadro da bicicleta sobre a ativação dos músculos do membro inferior / Effects of cycling with the knees close to the bicycle frame on the lower limb muscle activation

A mudança da posição do corpo sobre a bicicleta tem sido relacionada a alterações na ativação dos músculos do membro inferior. Desta forma, o objetivo do presente estudo foi comparar a ativação dos músculos "Tibialis Anterior", "Gastrocnemius Medialis", "Biceps Femoris", "Rectus Femoris", "Vastus Lateralis", "Adductor Longus" e "Gluteus Maximus" nas seguintes situações: 1) posição de referência (posição preferida); 2) posição de adução (joelhos tangenciando o quadro da bicicleta); 3) posição de abdução (joelhos afastados do quadro da bicicleta). Seis atletas com experiência competitiva em ciclismo foram avaliados por meio da eletromiografia de superfície (EMG). Todos pedalaram em suas próprias bicicletas montadas em um ciclosimulador, com carga de trabalho normalizada pelo VO2 de forma que a taxa de troca respiratória se mantivesse entre 0,8 e 1,0. A ativação muscular foi analisada por meio da comparação da média do envelope RMS e do período de ativação para cada um dos músculos, nas três posições avaliadas. Não foram observadas diferenças significativas para a média do envelope RMS e para o período de ativação dos músculos nas três posições avaliadas, à exceção do "Adductor Longus". Observou-se maior ativação (36 ± 6 por cento) deste músculo na posição de adução comparado a posição de abdução (25 ± 11 por cento) para um valor de significância de p = 0,02, sem diferenças em relação a posição de referência (27 ± 7 por cento). Estes resultados sugerem que não ocorrem alterações substanciais na ativação dos principais músculos do membro inferior quando a posição dos joelhos no plano frontal é alterada e a carga de trabalho é mantida, à exceção do aumento da participação do "Adductor Longus".

Cyclist's body position on the bike has been related to changes in muscle activation. Therefore, the aim of the present study was to compare the activation of Tibialis Anterior, Gastrocnemius Medialis, Biceps Femoris, Rectus Femoris, Vastus Lateralis, Adductor Longus e Gluteus Maximus muscles in three conditions: 1) reference position (preferred position); 2) adduction position (knees almost touching the bicycle frame); 3) abduction position (knees away from the bicycle frame). Six athletes with competitive experience in cycling were evaluated using surface electromyography. They pedalled using their own bicycles mounted on a wind-trainer, with a workload relative to the second ventilatory threshold. Muscle activation was defined by the mean value of the RMS envelope and by the activation period for the three evaluated positions. There were no significant differences in muscles' RMS or activation period between the three positions, except for the Adductor Longus muscle. In adduction position, this muscle was more activated (36 ± 6 percent), compared to the abduction position (25 ± 11 percent) for a significance level of p = 0.02, without significant differences for the reference position (27 ± 7 percent). These results indicate that there is no substantial difference in the activation of the most important muscles of the lower limb when the position of the knee is changed in the frontal plane for the same workload level, with the Adductor Longus as an exception.

Research on cervical muscle strength in air force pilots / 医用生物力学

Objective To evaluate neck muscular strength（NMS） of the air force pilots and its role in the circumstance of aerial dynamics. Method The tests were performed by using CME-1 Neck Muscle Training Machine with 149 pilots volunteered as test subjects. Each individual’s maximal isometric NMS was evaluated in the extension, flexion, left and right lateral bending directions within a single day. The NMS in each direction was tested for 10 times to choose the maximal peak value in each direction as the NMS for data analysis. The mean of overall peak value in each direction was calculated as the mean neck muscular strength (MNMS). The ratio(r) between MNMS and NMS was calculated to reflect the neck muscular endurance in pilots. Results The NMS in the flexion, extension, and left and right lateral bending directions was （132.0±42.2)N, （205.2±82.2)N, （174.3±76.4)N and （191.2±78.3)N respectively，the NMS in the extension or flexion direction was significantly different (P<0.001) compared with NMS in all the other directions，and the right NMS was significantly higher than the left NMS(P<0.001). The ratios between MNMS and NMS in the flexion, extension and left and right lateral bending directions were 74.24%,72.86%,72.75% and 68.72% respectively. Conclusions To Maximize the efficiency in flight performance and minimize neck injuries induced by +Gz, fighter pilots should be encouraged to perform more on land neck muscle strengthening exercises and improve their head positioning techniques during flight.

Aerodynamic Measure of the Phonation in Patients with Vocal Polyps and Vocal Nodules / 听力学及言语疾病杂志

Objective To investigate the aerodynamic characteristics of vocal polyps and vocal nodules.Methods Aerodynamic parameters of 58 patients with vocal polyps or vocal nodules and 30 normal adults were measured by Aerophone Ⅱ Voice Function Analyzer.The mean airflow rate,intraoral pressure,glottal resistance,glottal efficiency were compared among different group.Results The mean airflow rate,glottal resistance and glottal efficiency of vocal polyps,vocal nodules and normal adult were 254.50±36.02 ml/s,33.55±4.63 cmH_2O/(L·S),2.46±1.49,177.45±25.93 ml/s,38.83±8.88 cmH_2O/(L·S),7.75±3.71,118.44±29.98 ml/s,53.04±8.64 cmH_2O/(L·S),9.17±3.87,respectively.The difference between them was significant(P＜0.01).The difference of intraoral pressure between vocal polyps (8.97±1.36 cmH_2O) and normal adult (6.24±0.99 cmH_2O) was significant (P＜0.01).The mean airflow rate,glottal resistance,glottal efficiency were significantly different between vocal polyps and vocal nodules(P＜0.01).Conclusion The degree of vocal fold adduct and the effciency of voice production in vocal polyps is worse than that of vocal nodules.The aerodynamic parameters can make quantifiable,objective assessment in voice function of vocal polyps and vocal nodules.

Study on neck injuries in military pilots / 医用生物力学

Objective To investigate the present situation of neck injuries in military pilots, analyze possible factors that induce neck injuries and how such injuries could influence flight training, and provide suggestions for relevant physiological researches and engineering solutions. Method Questionnaires were carried out among 1 924 military pilots, including pilots of primary trainer, attacker, fighter, bomber, transporter and helicopter. The questionnaire consist of 2 parts: (1) pilots’ basic information, such as unit, age, type of aircraft, flying hours, height, weight, etc. (2) relevant issues on neck injuries, including symptoms and their influences on flight, reasons that cause the injuries, etc. Statistical analyses were conducted according to the questionnaire results. Results The investigation showed that 71.3% of the pilots had uncomfortable neck symptoms and 60.4% of them had befallen such symptoms during flight. 33.7% of the pilots had suffered neck pain and 19.2% of them reported that such pains took place during flight. Factors such as acceleration, weight of helmet and long duration of flight would be the main reasons resulting in the discomfort of neck. Bomber pilots showed the highest proportion either on the neck discomfort or on the neck pain. Conclusions Neck injuries have become the frequently occurring illness in Chinese military pilots and have affected their daily flight. The study also foresees an increased tendency on pilots’ neck injuries due to the growing requirements of flight load and training strength on fighter and attacker pilots. Therefore, great importance should be attached on neck injuries of military pilots and further studies should be conducted on physiological investigations and engineering solutions.

Hypernasality correlates with acoustics and aerodynamics

Particle Image Velocimetry Measurements for the Study of Nasal Airflow / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Several studies have utilized physical models or casts of the nasal cavity in an effort to understand the relationship between nasal anatomy and the distribution of inspired or expired airflow. This paper deals with the evaluation of nasal airflow characteristics during physiologic breathing in normal conditions. MATERIALS AND METHOD: The choana of a nasal model casting by a combination of rapid prototyping and solidification of clear silicone was connected to a pump that simulated physiological pressure in the upper airway system. Glycerin-water mixture was used as medium. The airstream was marked with polyvinyl spherical particles, and was observed through an solidificated clear silicone and analyzed with particle image velocimetry. RESULTS: Turbulence is clearly visible at the level of the head of the middle turbinate. The maximal velocity was recorded at the superior meatus. The flow rate was highest at the middle meatus. CONCLUSION: This model allows the investigation of airflow distribution and velocity under physiologic conditions. The main flow stream passes through the middle meatus.

Vocal Dynamic Studies before and after Laryngeal Microsurgery / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Perceptual acoustic measures are most often used to judge the outcomes and the objective analysis of phonosurgical results before and after the microlaryngeal surgery. However, they have rarely been reported in this country. The purpose of this study is to analyze aerodynamic and acoustic results before and after microlaryngeal surgery and to analyze the differences of the prognosis of various benign vocal cord lesions. MATERIALS AND METHODS: At Inha University Hospital, from June 1996 to August 1998, 245 microlaryngeal surgeries were done. Malignant lesions were excluded. And 118 (54 females and 64 males) out of 245 patients were followed up after the surgery: the acoustic and the aerodynamic studies before and 8 weeks after microlaryngeal surgery for benign lesions: vocal polyp, vocal nodule, Reinke's edema, intracordal cyst and hyperkeratosis. Seven measurements were performed: fundamental frequency, jitter, shimmer, noise to harmonic ratio as the acoustic analysis, maximal phonation time, mean flow rate and subglottal pressure as the aerodynamic analyses. RESULTS: Postoperative acoustic and aerodynamic data of vocal polyp, vocal nodule, Reinke's edema and intracordal cyst were improved, but those of hyperkeratosis were not improved. CONCLUSION: By comparing the acoustic and aerodynamic data before and after the microlaryngeal surgery, postoperative vocal function was defined more accurately and objectively. Jitter, shimmer, and MFR might be meaningful parameters accessing the quantitative changes in vocal quality before and after the microlaryngeal surgery.

Objective Evaluation of Phonation in the Normal and Pathological States / 听力学及言语疾病杂志

Mean flow rate (MFR) ,vocal intensity (I) ,pitch frequency(P) ,pitch perturbation (PP) and vocal efficiency (I/F) were measured simutaneously during sustained phonation of the vowel [i] at wide range levels of intensities in 158 nor mal subjects and the same parameters were measured at moderate vocal intensity level in 136 patients with various kinds of laryngeal diseases. PP indicates the amount of irregular vibration of vocal folds and I/F represents efficient transition from MFR to acoustic energy. When phonation at different intensities ,MFR,P and I/F increase but PP decreases when I increases. At moderate intensity phonation, there are positive correlations between MFR and I,and between I and P but negative correlation between MFR and I/F,between I(male) and PP,and between P(fe-male) and PP.Most of the patients with laryngeal diseases showed higher MFR and PP but lower I/F than normal subjects.MFR, PP and I/F could be used as objective and quantitative parameters with I and P as reference parameters in assessing laryngeal function of phonation.